It does not come from me first hand, as I actually have the Logitech Driving Force Pro, released specifically for GT4 (which I HIGHLY recommend, as it is the best FF wheel out there, and works wonderfully on the PC with GTR

), but it is from several members of another forum I frequent.
They had been using their momo wheels in GT3 for a long while.
I don't know if info was specifically put out there from Sony on the matter, but I do know that they all attempted to use it in GT4, only to find it does not work.